Coffee is a beverage of choice for many people around the world.
Actually, the commonly known “coffee beans”, roasted and used in the brewing of coffee for consumption as a beverage, are dried endosperm, i.e. seeds of coffee cherries. These coffee beans are typically referred to as green coffee beans prior to being roasted.
From the moment ripe coffee cherries are picked from their branches the inherent quality attributes of the respective cherries begin their natural degradation. Therefore, it is most desirable to limit the duration that cherries or wet parchments spend in what is referred to as the “unstable phase” of high “water activity” (aw 0.8-0.95) by subjecting the wet parchment or coffee cherries to a drying process to reduce the “water activity” of the cherries or wet parchments.
Around the world three processing methods are commonly used to dry post-harvest coffee cherries to shelf stable green coffee beans. Due to distinct differences between these processing methods brewed coffee reflects distinct differences in the overall cup profile/taste.
(Willen J. Boot, “Wet, dry, and everything in between: Coffee Processing”, Roast Magazine, January/February 2007).                A) The Washed Process, also commonly known as the Wet Process, involves the removal of pulp and mucilage through fermentation and subsequent washing before drying. The process produces a mild coffee with good acidity. The majority of the green beans produced around the world are being produced using this method.        B) In a Pulped Natural Process, also known as the Semi-washed Process, the cherries are pulped, the mucilage is mechanically removed and dried with the parchment. When managed well, this method produces a more distinct coffee than the Washed Process.        C) The Natural Process, also known as the Dry Process, involves the drying of the entire coffee cherry. After drying the entire hull is mechanically removed from the dried cherry to reveal the green beans. This process is hard to manage. When done well it produces a coffee that is much sweeter and has a bigger body (a sensory mouth-feel).        
Each of the above drying methods has specific draw-backs that affect the quality of the green bean.
When the duration of the “unstable phase” after picking is prolonged, the wet parchment or the cherries being dried are prone to potential Ochratoxin A (OTA) contamination. OTA is a natural poison that is highly toxic affecting the kidneys and was classified by the International Agency for Research on Cancer as a possible human carcinogen. It is produced by a fungi that affects coffee and other plants such as cereals and cocoa (Food and Agriculture Organization of the United Nations Reference: http://www.fao.org/ag/magazine/0607sp1.htm).
The Wet and Semi-dry processing methods require capital expenditure for equipment and drying facilities. All methods currently in use are extremely labour intensive and often require high skill level which may be lost in the transfer of knowledge from farmer to farmer. Unfortunately, significant deviations from the correct processing steps will affect the green bean, and after being roasted can produce an undesirable taste when brewed.
The Washed and Pulped Natural Process also have associated environmental problems, as they generate environmentally unfriendly effluents. These effluents (wastewater) result in water pollution and can potentially contaminate drinking water. Hence the wastewater needs to be treated adding to the cost of the process. Wastewater treatment presents major problems in developing countries where a significant proportion of coffee is produced.
Accordingly, it is an object of the present invention to provide a processing method which at least partially alleviates or ameliorates at least one or more problems identified with the processing methods discussed above.
Advantageously, it has been found through experiments that the coffee processed by the present invention has properties that are believed to give rise to a distinct taste and aroma, and a highly desired flavour profile, including but not limited to, increased sweetness and reduced bitterness, potentially due to an increased reducing sugar content and a reduced caffeine content in the coffee beans obtained using the processing method.